1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a small size for portable mobile communication devices or game devices.
2. Description of the Related Art
Information processing devices have been rapidly developed in a trend with various architectures, functions and faster information processing speed. Information processed in these information processing devices has an electrical signal format. In order to visually confirm information processed in the information processing device, a display device as an interface is necessary.
A liquid crystal display device, which is lighter and smaller than a CRT type display device, has been developed. The liquid crystal display device enables a full color display with a high resolution. As a result, the liquid crystal display device is widely used for a monitor of a computer, a television receiver, and another display device.
When a voltage is applied to a liquid crystal cell, a molecular arrangement of the liquid crystal is changed to cause a change in optical properties. As a result, visual properties are changed to display various images.
Liquid crystal display devices are divided into to a TN (Twisted Nematic) type and an STN (Super-Twisted Nematic) type. The liquid crystal devices are also divided according to the driving type into an active matrix display type that uses a switching device, and a TN liquid crystal and a passive matrix display type using an STN liquid crystal.
The active matrix display type is used in a TFT-LCD and drives an LCD by using a TFT as a switching device. The passive matrix display type does not use any transistor and does not need a complex circuit.
Further, liquid crystal display devices are divided into a transmissive liquid crystal display device using a backlight and a reflective liquid crystal display device that uses an exterior light source according to a method for using a light source.
The transmissive liquid crystal display device which uses the back light as a light source has a heavy weight and a large volume by the existence of the back light, but is widely used since it independently displays an image without using an exterior light source.
In particular, a liquid crystal display device having a properly reduced size for portability is demanded according to the rapid development of the communication devices. Thus, a display device is desired which has light weight, thin thickness and small size as well as high display quality to be applied to the mobile communication devices and to the game devices considering portability thereof.